1. Field of the Invention
The present invention relates to a data communication apparatus, and more particularly to a data communication apparatus such as a facsimile device capable of transmitting a sub-address signal according to the ITU-T recommendation.
2. Description of the Related Art
In conventional facsimile devices capable of transmitting a sub-address signal, it is possible to issue a sub-address signal to request a receiving facsimile device to perform relay broadcasting. However, there is no standard or recommendation as to relay broadcasting result notification returned from a facsimile device that performs relay broadcasting in response to a request to a facsimile device that issued the request.
A problem arising from the absence of the standard is that when a facsimile device that has requested relay broadcasting wants to receive notification of the result of relay broadcasting, a facsimile device that has performed relay broadcasting in response to the request sometimes sends no notification of the result of the relay broadcasting. In some cases, when a facsimile device that has requested relay broadcasting does not need notification of the result of relay broadcasting, a facsimile device that has performed relay broadcasting in response to the request sometimes sends notification the result of relay broadcasting.
In view of the above, it is an object of the present invention to provide a data communication apparatus capable of requesting and receiving notification of the result of relay broadcasting to or from another data communication apparatus in an adequate manner that prevents an unacceptable request from being sent and a useless notification message from being returned.